The proper noun is spelled Mississippi (a river, US state, and a lake in Ontario).
The spelling can be remembered because the consonants are paired: SS, SS, and PP, with I's between them.
Biloxi, as in the place in Mississippi.
Mississippi
MISSISSIPPI
it is mississippi
Mississippi
The state capital of Mississippi is Jackson.
MISSISSIPPI
you spell it Mississippi
Well, you cant actually "Mississippi", but if you mean spell, you've done fine.
Mississippi (always capitalize the "m")
That is the correct spelling of the proper noun (river or state) Mississippi.
Both the river and the US state names are spelled Mississippi.*One way to be sure that you have spelled it correctly is that you can see the four-letter combinations ISSI, ISSI, and IPPI in the correct form.